Image display device

ABSTRACT

To provide an image display device of the type use while worn on the head without giving a strange impression when used in everyday life. 
     An image display device  1  includes a main body  10  that can be worn on the head of a user, ad a display unit  20  for displaying a predetermined image in such a manner that the image is blurred or beyond the vision of the user when the user wearing the main body  10  on his or her head looks straight ahead, and that the user gets a clear vision of the image when the user moves his or her eyes away. The display unit  20  includes a pair of display units for the right and left eyes which are provided on or in the main body  10  at a position that cannot be seen from anyone other than the user.

TECHNICAL FIELD

The present invention relates to a small image display device that canbe used while worn on the head.

BACKGROUND OF THE INVENTION

Head mounted displays (HMDs), which are used while worn on the head toplace a video screen in front of each eye of the user, find applicationsin various fields including the field of virtual reality. Typical HMDsare designed in the shape of a frame of goggles or large glasses thatblock but outside light and force the user to see only the HMD'spictures. With an HMD used, the user can view images irrespective of thedirection he or she faces but then again it gives the user visualisolation from the surrounding environment.

In recent years, small image display devices have been proposed thatallow users to view images along with the surrounding environment bymeans of presenting the images in a certain part of the field of vision.Such image display devices are not designed for image presentation only.Instead, the main purpose of it is to aid the everyday life. Images thatare displayed are letters and numeric characters unlike the conventionalHMDs.

For example, Japanese patent laid-open document (JP-A-7-209600) proposesan image display device having a liquid crystal display (LCD), areflecting mirror, an ocular lens and other components contained withina single housing which is attached to a glasses or sunglasses frame. Thehousing is placed on top of either right or left lens of the glassesover the outside surface of it. An image that is displayed on the LCD isdirected to one eye of the user in a diagonal down direction through thereflecting mirror, the ocular lens, and the lens of the glasses.

The image display device disclosed in the aforementioned reference isdesigned so that it is attached to the glasses, which spoils itsappearance. Therefore, the use of an image display device as above ineveryday life gives a strong impression of something strange to thosearound the user.

An object of the present invention is to provide an image display deviceof the type used while worn on the head without giving a strangeimpression when used in everyday life.

SUMMARY OF THE INVENTION

An image display device that solves the aforementioned problem comprisesa main body that can be worn on the head of a user, and display meansfor displaying a predetermined image in such a manner that said image isblurred or beyond the vision of said user when said user wearing saidmain body on his or her head looks straight ahead, and that said usergets a clear vision of said image when said user moves his or herstraight-looking eyes away, said display means being provided on or insaid main body at a position that cannot be seen from anyone other thansaid user.

Such an image display device has the display means that cannot be seenfrom anyone other than the user. Therefore, no one is aware of thedisplay means and accordingly no one feels a strange impression whensaid image display device is used in everyday life.

For example, said main body may be provided in the shape of a glassesframe. At least a part of said frame is positioned in such a manner thatsaid part is not very clearly visible for said user when said userwearing said main body on his or her head looks straight ahead. Saiddisplay means is provided on or in said part of said frame. The imagedisplay device does not look any different from conventional glasses,giving no strange impression in everyday life.

Alternatively, said main body may comprise an elongated front unit thatis placed in front of the eyes of said user along the direction parallelto a line connecting the right and left eyes when said main body is wornon the head of said user, and a fixing unit for use in mounting saidfront unit on the head of said user. In this case, said display means isprovided on or in said front unit. Such a main body may be hard to fitinto our everyday life as compared with a main body having the shape ofa glasses frame. However, it has a simple structure and is designedwell. The front unit in this case may be, for example, in the shape of arod or a thin, narrow plate. The front unit may have a diameter of about10 mm to 30 mm when shaped as a rod. The front unit may have a width ofabout 10 mm to 50 mm when shaped as a thin, narrow plate. The diameterof the rod-shaped front unit and the width of the plate-shaped frontunit are not required to have a same dimension along the length thereof.

The front unit may be deformed more or less in the up and downdirections with respect to the face of the user. Alternatively, it maybe deformed more or less in the right and left directions with respectto the face of the user.

The display means may have various configurations. As an example, saiddisplay means has a light source, liquid crystal display means that usessaid light source for the backlight thereof and an optical system toguide an image produced by said liquid crystal display means to theoutside of said main body, all of which are contained within said mainbody.

The image display device may be downsized by using said main body forreceiving an image signal by wire or wireless to display an image fromoutside and by using said display means for displaying an image fromsaid image signal received by said means. An example of the image signalincludes a video signal and an RGB signal.

Said display means may be a pair of display means that are provided onor in said main body in one to one correspondence with the right andleft eyes of said user. Since these display means provide images at aposition or positions close to the eyes of the user when worn, thedisplay means corresponding to the respective eyes allow easy productionof sophisticated images such as three-dimensional images.

Said display means may be configured in such a manner that said usergets a clear vision of said images to be displayed only when said userwearing said main body on his or her head moves his or herstraight-looking eyes down. This configuration allows the user to watchhis or her step while viewing said images displayed by the displaymeans. This makes mobile use of said image display device easy.

Another image display device of the present invention may comprise amain body in the shape of a glasses frame and display means that isprovided on or in said main body to present an image to a user, saiddisplay means having a light source, liquid crystal display means thatuses said light source for the backlight thereof, a reflecting mirror toguide an image produced by said liquid crystal display means to theoutside of said main body and an ocular lens for directing said image tosaid user, all of which are contained within said main body, said ocularlens being not very clearly visible for said user when said user wearingsaid main body looks straight ahead, which becomes clearly visible onlywhen said user moves his or her straight-looking eyes away, said ocularlens being provided at a position that cannot be seen from anyone otherthan said user.

Another image display device of the present invention may comprise amain body having an elongated front unit and a fixing unit for use inmounting said front unit on the head of said user, and display meansthat is provided on or in said main body to present an image to saiduser, said display means having a light source, liquid crystal displaymeans that uses said light source for the backlight thereof, areflecting mirror to guide an image produced by said liquid crystaldisplay means to the outside of said main body and an ocular lens fordirecting said image to said user, all of which are contained withinsaid main body, said front unit being placed in front of the eyes ofsaid user along the direction parallel to a line connecting the rightand left eyes when said main body is worn on the head of said user, saidocular lens being not very clearly visible for said user when said userwearing said main body looks straight ahead, which becomes clearlyvisible only when said user moves his or her straight-looking eyes away,said ocular lens being provided at a position that cannot be seen fromanyone other than said user.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view showing the whole of an image display device accordingto an embodiment;

FIG. 2 is a view showing details of a display unit;

FIG. 3A is a view showing the state that a user wearing the imagedisplay device looks straight ahead, whereas FIG. 3B is a view showingthe state that the user looks at the display unit;

FIG. 4 is a perspective view of an image display device according to afirst modification;

FIG. 5 is a side view schematically showing the state that the user iswearing the image display device in FIG. 4 on his or her head;

FIG. 6 is a perspective view of an image display device according to asecond modification; and

FIG. 7 is a side view schematically showing the state that the user iswearing the image display device in FIG. 6 on his or her head.

BEST MODE FOR CARRYING OUT THE INVENTION

An embodiment of the present invention is described in detail below withreference to the drawing.

FIG. 1 is an outline view of an image display device 1 of the presentinvention.

The image display device 1 comprises a main body 10 in the shape of aglasses frame and display units 20 for displaying an image. The imagedisplay device 1 is a device that receives an image signal, such as avideo signal or an RGB signal, by wire or wireless from an imageprocessor which is not shown, to produce images from the image signal onthe display units 20.

The main body 10 is designed in such a manner that the user can wear theimage display device 1 on his or her head. The main body 10 comprisestemples 11 which fit over the user's ears to keep the image displaydevice 1 on when the user wears it on his or her head, and a frame 13 onwhich or in which the display units 20 are provided. The frame 13 can befitted around lenses 14 as in normal glasses or sunglasses. Nose pads 15are attached to the frame 13 in order for the image display device 1 torest stably while worn by the user.

The main body 10 has an audio output device 12, such as a speaker or anearphone, through which sound comes out for the user. The audio outputdevice 12 is integrally provided in the temple 11. Since the audiooutput device 12 rests close to the user's ear(s) when the user wearsthe image display device 1, the output sound which comes out through theaudio output device 12 is not required to be so loud.

While not illustrated in the drawing, the main body 10 has a cable or anantenna to receive image signals from the image processor by wire orwireless. The received image signal is supplied to the display units 20.Simultaneous reception of the sound which comes out through the audiooutput device 12 and the image signal from the image processor achieveseasier synchronization between the image and sound.

The display units 20 are provided on or in the frame 13 of the main body10. Each display unit 20 is designed as shown in FIG. 2. The displayunit 20 comprises a light source 21, a liquid crystal display 22 andreflecting mirrors 23 and 24, all of which are contained within theframe 13. An ocular lens 25 is also provided on or in the frame 13. Theliquid crystal display 22 uses the light source 21 for the backlightthereof. It produces images from the image signal received by the mainbody 10. The image produced by the light source 21 and the liquidcrystal display 22 is guided to the outside of the frame 13 through theoptical system consisting of the reflecting mirrors 23 and 24 and theocular lens 25.

The ocular lenses 25 are provided on or in the frame 13. When the userwearing the image display device 1 looks straight ahead, the images fromthe ocular lenses 25 are blurred or beyond the vision of the user (FIG.3A). In the case of this embodiment, the user should move his or hereyes down to look at lower portions of the frame 13 in order to view theimages from the ocular lenses 25 (FIG. 3B).

The position of each ocular lens 25 is not limited to the aforementionedone. They may be provided at upper or side portions of the frame 13. Inany cases, the images from the ocular lenses 25 are invisible from theuser when the user looks straight ahead. It can be visible only when theuser moves his or her eyes to the direction of the ocular lenses 25.

The ocular lenses 25 are provided on or in the frame 13 on the sidefacing to the user in such a manner that only this particular user cansee them while he or she is wearing the image display device 1. Thus,anyone other than the user cannot see the ocular lenses 25.

As apparent from the above, all the components of the display units 20except for the ocular lenses 25 are housed within the frame 13. Theocular lenses 25 are provided at a hidden position that is invisiblefrom anyone other than the user. Thus, no one other than the user willbe aware of the display units 20. The image display device 1 gives nostrange impression to others when used even in everyday life.

The image display device 1 as described above can be used as in the caseof ordinary glasses. More specifically, the images displayed on thedisplay units 20 do not catch the user's eyes while the user wearing theimage display device 1 looks straight ahead. Therefore, the sameusability as ordinary glasses or sunglasses is available. The userbecomes aware of the images only when he or she moves his or her eyes tothe ocular lenses 25.

<<First Modification>>

The image display device 1 may by modified as shown in FIGS. 4 and 5.

FIG. 4 is a perspective view of an image display device 1X according toa first modification. FIG. 5 is a side view showing how the imagedisplay device 1X is used. Similar reference numerals in FIGS. 4 and 5to those used in FIGS. 1 to 3 represent similar components and parts tothose shown in FIGS. 1 to 3. Repeated description will be omitted.

Details of the image display device 1X shown in FIGS. 4 and 5 areessentially the same as those of the image display device 1 described inthe aforementioned embodiment.

The difference of the image display device 1X from the image displaydevice 1 lies in their structure: the main body 10 of the image displaydevice 1 is designed like a glasses frame having the temples 11 and theframe 13 whereas the main body 10 of the image display device 1X hastemples 11 and a front unit 16.

The front unit 16 of the image display device 1X has an elongated shape,more specifically, a shape of a thin, narrow plate.

The front unit 16 is provided with display units 20 (20R, 20L) similarto those of the image display device 1. The display units 20 are placedon the backside (on the side fronting onto the user's face when the mainbody 10 is mounted on the user's head) of the front unit 16 in the shapeof a thin, narrow plate. In addition, while not necessarily beingrequired, the display units 20 of this embodiment are attached to thefront unit 16 in such a manner that they are beyond the beholder'svision when the user wearing the main body 10 on his or her head is seenfrom an anterior view. The width of the front unit 16 is, but notlimited to, 15 millimeters.

Each of the display units 20R and 20L in this modification 1 has agenerally rectangular parallelepiped shape with one surface opened tothe air. They can be attached to the backside of the front unit 16 bymeans of fitting them into respective hollow sockets 17 (sockets 17R and17L for the right and left eyes, respectively) formed on or in thebackside of the front unit 16.

FIG. 5 is a side view schematically showing the state that the user iswearing the image display device 1X on his or her head. As apparent fromFIG. 5, the display units 20 of the image display device 1X are attachedto the front unit 16 at an angle that allows the user to see the imagesproduced by them when the user moves his or her eyes down. The frontunit 16 is located slightly below the eyes of the user when the userwears the main body unit 10 on his or her head so that the user can seethe images produced by the display units 20 when the user moves his orher eyes down. Details of the display units 20 are the same as that ofthe image display device 1.

In this embodiment, the right eye can catch the image displayed on thedisplay unit 20R for the right eye whereas the left eye can catch theimage displayed on the display unit 20L for the left eye when the userlooks down at an angle of, but not limited to, 45 degrees with his orher head facing the front (see FIG. 5). This angle is preferably atleast 20 degrees in order to give a forward field of vision of the userduring the time when the user does not look at the images displayed onthe display units 20R and 20L. The aforementioned angle is preferablynot larger than 70 degrees because an unduly large angle prevents theuser's easy seeing of the images displayed on the display units 20R and20L. The sockets 17R and 17L are fixed to the front unit 16 at such anangle that the user can look at the display units 20R and 20L over theaforementioned range of angles.

<<Second Modification>>

Another modification (second modification) of the image display device 1is shown in FIGS. 6 and 7. Similar reference numerals in FIGS. 6 and 7to those used in FIGS. 4 and 5 represent similar components and parts tothose shown in FIGS. 4 and 5. Repeated description will be omitted.

FIG. 6 is a perspective view of an image display device 1Y according toa second modification. FIG. 7 is a side view schematically showing thestate that the user is wearing the image display device 1Y on his or herhead.

Most of the details of the image display device 1Y shown in FIG. 6 arethe same as those of the image display device 1X.

The difference between them lies in the shape of their front unit 16.The front unit 16 of the image display device 1X according to the firstmodification has a shape of a thin, narrow plate whereas the front unit16 of the image display device 1Y according to the second modificationhas a shape of a rod with a generally circular cross section in thisembodiment. The diameter of the front unit 16 is, but not limited to, 13millimeters.

In the image display device 1Y, the front unit 16 is provided with thedisplay units 20 (20R, 20L). The display units 20 are placed on thebackside (on the side fronting onto the user's face when the main body10 is mounted on the user's head) of the front unit 16, as in the caseof the image display device 1X. In addition, while not necessarily beingrequired, the display units 20 of this embodiment are attached to thefront unit 16 in such a manner that they are beyond the beholder'svision when the user wearing the main body 10 on his or her head is seenfrom an anterior view.

In this embodiment, depressions 16A are formed in the backside of therod-shaped front unit 16 at positions corresponding to the right andleft eyes of the user (see FIG. 6). The display units 20 are fitted intothe respective depressions, which makes the beholder difficult to seethe display units 20 when the user wearing the main body 10 on his orher head is seen from an anterior view.

As apparent from FIG. 7, the display units 20 of the image displaydevice 1Y are attached to the front unit 16 at an angle that allows theuser to see the images produced by them when the user moves his or hereyes down. The front unit 16 is located slightly below the eyes of theuser when the user wears the main body unit 10 on his or her head sothat the user can see the images produced by the display units 20 whenthe user moves his or her eyes down.

In this embodiment, the right eye can catch the image displayed on thedisplay unit 20R for the right eye whereas the left eye can catch theimage displayed on the display unit 20L for the left eye when the userlooks down at an angle of, but not limited to, 45 degrees with his orher head facing the front (see FIG. 7). This angle is preferably atleast 20 degrees in order to give a forward field of vision of the userduring the time when the user does not look at the images displayed onthe display units 20R and 20L. The aforementioned angle is preferablynot larger than 70 degrees because an unduly large angle prevents theuser Is easy seeing of the images displayed on the display units 20R and20L. The depressions 16A are formed in the front unit 16 at such anangle that the user can look at the display units 20R and 20L over theaforementioned range of angles.

1. An image display device comprising a main body in the shape of aglasses frame and display means that is provided in said main body topresent an image to a user; said display means having: a light source,liquid crystal display means that use said light source for thebacklight thereof, a reflecting mirror to guide an image produced bysaid liquid crystal display means to the outside of said main body andan ocular lens for directing said image to said user, all of which arecontained within said main body; said ocular lens being not very clearlyvisible for said user when said user wearing said main body looksstraight ahead, which becomes clearly visible only when said user moveshis or her straight-looking eyes away, said ocular leans being providedat a position that cannot be seen from anyone other than said user. 2.The image display device as claimed in claim 1, wherein said main bodycomprises means for receiving an image signal by wire or wireless todisplay an image from outside, said display means being adapted todisplay an image from said image signal received by said means.
 3. Theimage display device as claimed in claim 1, wherein said display meansis a pair of display means that are provided in said main body in one toone correspondence with the right and left eyes of said user.
 4. Theimage display device as claimed in claim 1, wherein said display meansis configured in such a manner that said user gets a clear vision ofsaid images to be displayed only when said user wearing said main bodyon his or her head moves his or her straight-looking eyes down.
 5. Animage display device comprising a main body having an elongated frontunit and a fixing unit for use in mounting said front unit on the headof said user, and display means that is provided in said main body topresent an image to said user; said display means having: a lightsource, liquid crystal display means that use said light source for thebacklight thereof, a reflecting mirror to guide an image produced bysaid liquid crystal display means to the outside of said main body andan ocular lens for directing said image to said user, all of which arecontained within said main body, said front unit being placed in frontof the eyes of said user along the direction parallel to a lineconnecting the right and left eyes when said main body is worn on thehead of said user; said ocular lens being not very clearly visible forsaid user when said user wearing said main body looks straight ahead,which becomes clearly visible only when said user moves his or herstraight-looking eyes away, said ocular lens being provided at aposition that cannot be seen from anyone other than said user.
 6. Theimage display device as claimed in claim 5, wherein said main bodycomprises means for receiving an image signal by wire or wireless todisplay an image from outside, said display means being adapted todisplay an image from said image signal received by said means.
 7. Theimage display device as claimed in claim 5, wherein said display meansis a pair of display means that are provided in said main body in one toone correspondence with the right and left eyes of said user.
 8. Theimage display device as claimed in claim 5, wherein said display meansis configured in such a manner that said user gets a clear vision ofsaid images to be displayed only when said user wearing said main bodyon his or her head moves his or her straight-looking eyes down.